As promised, Windows 7 Beta is officially available to download for the general public. You’ll need a Windows Live email address to be able to download it. You can download the Beta from here where you can either choose between the 32-bit and the 64-bit versions.
I just tried to download the 64-bit version but the server is experiencing “technical difficulties”, in other words, a lot of traffic… who knows why :). I’ll be checking in a few more hours. If you are able to download, please let me know.